Loss of bass & full spectrum sound

Hi @fishing716 
I'm just wondering if you ever solved this problem. 9 years later I hope so! Anyway, I was searching the internet for any insights on this. I seem to be experiencing exactly the loss of bass that you've described. The Bass sounds hollow and thin. But the first few days of owning the amp, I was blown away by the clarity of sound. Music had amazing bass & clarity even at low volumes. Now I get nothing like it. The amp will still play loud, and I do get bass frequencies, but everything sounds very average now.  Anyway, if you found a solution, I'd love to hear it. I'm going to call my supplier tomorrow and explain the problem. I've never experienced an amp sounding so good one day, then just so so the next.

I've now rung Yamaha and some service centres. They are inclinded to think that the problem we are both descibing is more so the speakers/drivers are the issue.... not the amp. I really hope my speakers are ok... and an amp replacement will fix the issue... but it sounds unlikely. The amp I just bought is the Yamaha RN803D by the way...

I have experienced the same with my Pass Labs 250. It is not speakers as I have several. I just wonder if it's the density or the air in the room at the time. Mine has no pattern to it. I get blow you out the room bass most of the time, but then all overtime the amp is just thin sounding in the bass. Come to think of it, this has happened with several of my amps. I have no answer.

i had that same problem, i had wrote in to the forums as well.  what it turn out to be was the output cap or trans in my amp were going bad and jeff at cj called me to tell me the amp was getting a little long in the tooth.  i sent it in and they rebuilt it and that was it....bass is back and dynamics have retuned.  i dont know what you amp is or how old it is but if you have psb speakers they need lots of power....